by Cindy Lockworth

In the veterinary team of a biomedical
research facility, we strive to maintain the health and welfare of
animals, as healthy animals produce valid and valuable data needed for
vital research studies. Occasionally, we encounter unanticipated
clinical cases that can be both challenging and interesting. This
occurred during a recent study involving swine in our facility.

Due to their size and their specific anatomic and physiologic
characteristics, swine have become extremely valuable in the field of
biomedical research as surgical models, as well as research models for
specific diseases such as atherosclerosis and septic shock. Pigs
utilized in research are generally obtained from a range of health
status levels which may include open/closed herds, high health herds or
specific pathogen free sources. Thus, variations in management practices
and the overall susceptibility of swine to certain conditions persist.

Recently, we had a 9 month old castrated Yorkshire enrolled in an
IACUC approved study. The pig was part of a study involving two surgical
procedures that did not require body cavity penetration. Following a
single instance of regurgitation 3 months after surgery, the pig was
clinically normal in appearance until 5 months post-op, at which time
the pig began a 3 week period of repeated incidents of regurgitation.

Prior to the onset of clinical signs, the pig was well conditioned,
active, and growing. During the 3 weeks of regurgitation, the pig was
observed to have a voracious appetite, yet began a slow and consistent
decline in weight. The pig remained adequately hydrated. With the
exception of declining body condition, no other abnormalities were noted
upon physical exam.

From the onset of regurgitation until euthanasia, the pig was treated
medically. Omeprazole and ondansetron were administered. Simplicef was
given for a 6 day duration due to nasal discharge. Feed was modified in
frequency, volume, and consistency; consistency ranged from thick gruels
to liquid soy protein diet.

As is commonly the case in the research environment, no diagnostic
work-up was performed in life. However, differentials for regurgitation
included stricture, esophagitis, megaesophagus, or mass/tumor. Necropsy
and histopathology investigations were performed. Gross examination
confirmed the diagnosis of chronic gastroesophageal stricture with
acquired megaesophagus.

Ulceration of the pars oesophagea region of the stomach has been
described since the 1950’s in swine. Studies have shown that 32-65% of
slaughter pigs have evidence of gastric ulcers. The pathogenesis remains
unknown.

In this unusual and interesting case, the pig developed a persistent
ulcer in the region of the gastroesphageal junction. Chronic
inflammation and fibrosis caused a stricture of the lumen, resulting in a
4 mm diameter lumen which allowed only water to pass from the esophagus
into the stomach. Although the differential diagnoses for gastric
ulceration includes various infectious agents, in the research setting,
stress is presumed to be a leading cause.

Who We Are

William Singleton, DVM, ACLAM, Dipl.

A board certified laboratory animal veterinarian having over 15 years
experience working in the laboratory animal field. He has over 7 years
experience in the development and implementation of training programs in
the pharmaceutical industry and academic institutions. William is an
active member of the laboratory animal community and professional
organization that promotes the health and well being of research
animals. His strong passion and vision for quality training has been
part of the driving force behind the creation of ACTS.

Paula Clifford, MLA, RLATG, CVT.

Paula Clifford strongly believes in the empowerment of the individual
through knowledge resulting in the highest quality of care and use for
research animals. She has fourteen years experience in the laboratory
animal science industry, the last ten focused on developing,
implementing, providing, and assessing training programs in support of
animal based biomedical research. Paula has a Masters of Liberal Arts
from the University of Pennsylvania. Her graduate work focused primarily
in training program evaluation for animal care and use programs. She
obtained her Bachelors degree from Rutgers College, and an Associate’s
Degree in Applied Science (for Veterinary Technology) from Camden County
College. She is currently a licensed veterinary technician and AALAS
Certified as a Registered Laboratory Animal Technologist. In 2009, she
was recognized for her contributions to training in the laboratory
animal science field at National AALAS by being awarded the Collins
award. She is an active member of many organizations that promote
education.

Our promise is to engulf your work environment in optimism and empower creative thinking, while taking your staff on a journey to achieving their highest potential.